This invention relates to electronic stethoscopes and in particular to a stethoscope in which the output may be compared both by sound and visually on a scope with various sound signals prerecorded on a memory medium.
Various pathological conditions of a patient are revealed by auscultation examination. A normal heart and lungs produce normal sounds which are detected by the stethoscope, and if any abnormalities are detected proper corrective steps may be taken Therefore, it is extremely important for a medical diagnostician to recognize and understand normal and abnormal heart and lung sounds.
There are many heart sounds that must be learned by the diagnostician. The human heart has four chambers. During the diastolic or relaxed period, blood flows through the tricuspid valve into the right ventricle and oxygenized blood flows through the mitral valve into the left ventricle. At the end of this very short diastolic period the mitral valve closes followed by the tricuspid valve and the heart muscle contracts in systole while blood is pumped from the right ventricle through the pulmonary valve and blood is pumped from the left ventricle through the aortic valve. There is a sound, called S1, that occurs at the closure of the mitral and tricuspid valves and a sound, S2, that occurs at the closure of the aortic and pulmonary valves.
With the presence of heart disease the individual sounds are often split and may be heard as two sounds on each of the two basic S1 and S2 sounds. And in addition to the basic sounds, there are pathologic sounds which may be caused by blood passing through a tight valve or a pathologically enlarged valve opening. And certain disease processes may cause rubbing sounds produced by rubbing of the heart wall on the tissue covering that surrounds the heart. Certain diseases can change or vary the heart sounds. For example, if S1 appears to be louder than S2, it suggests a tightening of the mitral valve or mitral stenosis, whereas an unusually soft S2 suggests mitral regurgitation. Heart disease is suggested if any component separation occurs during expiration, if separation seems excessive, or if one component is persistently missing.
Lung sounds also have two components, that produced by inspiration and that by expiration. With a presence of disease in the lungs the normal lung sounds are disrupted and certain pathologic crackles, rates and wheeze sounds are produced which, in most instances, would point to a certain disease going on in the patient""s pulmonary and even systemic system.
The foregoing material discusses only a small fraction of the various sounds that may be detected with a stethoscope. There is a multitude of murmurs, hums and clicks that may be heard at various body locations while in various positions. It is thus apparent that the science of auscultation is difficult and that certain medical technicians, such as ambulance technicians or student who may not have thoroughly mastered the science, would benefit greatly from a stethoscope that included a diagnostic capability.
Briefly described, this invention is for a self-contained electronic stethoscope in a housing that includes a prerecorded record of typical sounds, a recorded image of the external pulse recordings of the sound and a suggested diagnosis. The electronic stethoscope normally outputs into a small speaker and to a small oscilloscope for viewing the signal, and depressing a momentary contact switch will divert the prerecorded record output to the speaker and scope for comparison with the stethoscope sounds